Radiographic images, such as X-ray films, and Magnetic resonance imaging ("MRI") and computerized tomograph (CT) transparencies have traditionally been reviewed by a diagnosing physician such as a radiologist on a film viewer, on which a series of images in a patient study are displayed in groups of two or more. Different image series, generated by processing the data captured during a patient scan in different ways, are typically provided. The different image series may display the same portions of the patient's anatomy but processing reduces the amount of information in the image to allow for films having sufficient pixel depth to provide the detail needed for diagnosis in the tissue of interest. The film viewer may be a static light box or a motorized film viewer. A motorized film viewer consists of vertically positioned light boxes and an endless belt on which the films are mounted and which passes the films in front of the light boxes. Motorized film viewers are controlled by the radiologist using foot pedals which activate the motorized viewer to cause the films to be moved to the left or to the right (or in some cases, up and down) to permit viewing of the desired portions of the film series. The images are usually presented in a standard sequence, usually in the order of image capture. The radiologist will typically dictate a medical study into a tape recorder while viewing the films, for later transcription. The films and transcribed dictation are stored in a patient's file.
Filmless image systems have also been proposed and used. Filmless systems have been used in connection with handling both MRI images, and computer tomography images generated by processing X-ray image data to generate a series of "slices" through the human body. Such systems historically have presented all the image data captured by the MRI or tomography equipment, as opposed to in film images (where the medical technician will expose films only for selected series of images of clinical interest). This mass of information has proven unwieldy to review and consider, as instead of filtering the image data through the selection of a skilled technician, all the image data is presented to the diagnosing physician. Another disadvantage of this approach is that it does not provide an "image of record," that is, the basic image(s) relied on by the physician in making the diagnosis. Given the limitations of the image processing equipment, it took a significant amount of time to review the numerous image series. Such systems are far less efficient than the conventional light boxes, which allowed the radiologist to rapidly review numerous series of images to find the few images showing the pathological condition of interest. Other filmless systems have been proposed in which a series of images are presented to the diagnosing physician simultaneously. One such system is described in Hilton, U.S. Patent No. 5,452,416.
However, all of these systems have proven awkward in actual use, as they require use of mouse, keyboard, trackball or other device to navigate through the image series. These control devices severely impair the diagnosing physician's ability to concentrate on the images presented and to relate the images to his knowledge built up through years of practicing medicine. The constant need to correctly position and actuate a mouse and trackball to navigate through images has made the use of such systems far less efficient than conventional film systems. In conventional film systems, the image navigation is effortless, requiring no more than movement of the eyes over a wall filled with film images, allowing the diagnosing physician to concentrate on the real work of interpreting the medical images to reach a diagnosis. Such control devices thus limit the fluid navigation by the diagnosing physician through the image series, and tie the physician to a single position. These control devices are also awkward for a diagnosing physician who may need to refer to materials such as textbooks or prior film-based medical studies for comparison. These devices also may impede the physician's ability to easily dictate the medical study, as most dictation equipment requires a handheld recorder or microphone, thus requiring the physician to either put down and pick up the microphone each time he needs to activate the mouse or trackball to see further images. Alternatively, the physician might learn to work two handedly, but this creates additional complications, for example, if the physician also desired to turn pages in or otherwise refer to a text or other reference material.